Anode pins extraction apparatus for electrolytic reduction cells



Feb. 3, 1970 R. J. DILL 3,493,486

ANODE PINS EXTRACTION APPARATUS FOR ELECTROLYTIC REDUCTION CELLS FiledMay 5, 1965 6 Sheets-Sheet 1 INVENTOR RAYMOND JOSEPH DILL ATTORNEY 5Feb. 3, 1970 R. J. mu.

ANODE PINS EXTRACTION APPARATUS FOR ELECTROLYTIC REDUCTION CELLS 6Sheets-Sheet 2 Filed Hay 5, 1965 INVENT OR RAYMOND JOSEPH DILL yhzflwwmATTORNEY Feb. 3, 1970 R J DILL 3,493,486

ANODE PINS ExT'RATIoN APPARATUS FOR ELECTROLYTIC REDUCTION CELLS FiledMay 5, 1965 6 Sheets-Sheet 5 IHIIIHIIIHII INVENTOR RAYMOND JOSEPH DILLFeb. 3, 1970 R. J. DILL 3,493,436-

ANODE PINS EXTRACTION APPARATUS FOR ELECTROLYTIC REDUCTION CELLS Filedmay 5, 1965 6 Sheets-Sheet 4 INVENTOR RAYMOND JOSEPH DILL ATTORNEY Feb.3, 1970 DILL 3,493,486

' R. J. ANODE PINS EXTRACTION APPARATUS FOR ELECTROLYTIC REDUCTION CELLSFiled May 5, 1965 6 Sheets-Sheet 5 INVENT OR RAYMOND JOSEPH DILLATTORNEY Feb. 3, 1970 R. J. DILL ANODE PINS EXTRACTION APPARATUS FORELECTROLYTIC REDUCTION CELLS 6 Sheets-Sheet 6 Filed May 5. 1965 INVENTOR RAYMOND JOSEPH DILL United States 3,493,486 ANODE PINS EXTRACTIONAPPARATUS FOR ELECTROLYTIC REDUCTION CELLS Raymond Joseph Dill,Florence, Ala., assignor to Reynolds Metals Company, Richmond, Va., acorporation of Delaware Filed May 3, 1965, Ser. No. 452,493 Int. Cl.C22d 3/02, 3/12; E21b 19/16 US. Cl. 204-243 3 Claims ABSTRACT OF THEDISCLOSURE The present invention concerns a system for manipulatinganode pins or the like, such as those used to provide electricalconnections to a carbon anode in an electrolytic reduction cell. Moreparticularly, the invention relates to method and apparatus forextracting hot anode pins and resetting the pins while still hot.

Anode pins of iron or steel are conventionally em ployed with the carbonanodes of alumina reduction cells. In cells having Soderberg orself-baking anodes, the pins typically are arranged in rows along theside of the anode. As the carbon is consumed, the anode is loweredperiodically, and eventually it becomes necessary to remove thelowermost pins in order to avoid their becoming melted and contaminatingthe aluminum being produced.

Prior practice has been to remove and clean the pins prior to reusenotan easy task because, for one thing, the pins become securely anchoredin the baked carbon, and they are likely to be red hot unless the cellhas been shut down for some time which usually is not the case. Inaddition, the cleaning operation itself is troublesome, being bothdifiicult and time-consuming to perform.

It has been found, however, that the cleaning of such pins can beavoided altogether if they are reinserted in the carbon promptly, whilestill hot and before oxidation or other effects incident to cooling thepins result in formation of a strongly adherent deposit. In accordancewith the invention, therefore, a principal object is to provide forhandling hot anode pins, including the provision of apparatus forextracting and resetting such pins quickly and easily.

For a better understanding of the invention and its various objects,advantages and details, reference is now made to the presently preferredembodiment of the invention which is shown, for purposes of illustrationonly, in the accompanying drawings.

In the drawings:

FIG. 1 is a front view of the anode pin puller-driver apparatus inaccordance with the invention, shown in relationship to a reduction pot;

FIG. 2 is a top view of the puller-driver apparatus shown in FIG. 1;

FIGS. 3A and 3B are enlarged elevational views, partially sectioned toshow additional details of the pullerdriver mechanism seen generally inFIG. 1;

FIG. 4 is a section taken at lines 44 in FIG. 2;

FIGS. 5, 6 and 7 are sections taken respectively at lines 5-5, 66 and 77in FIG. 3B; and

FIG. 8 is a schematic of the hydraulic control system.

The general arrangement of apparatus in accordance atent 3,493,486Patented Feb. 3, 1970 with the invention and its manner of operation areshown in FIG. 1, a front view of the modified fork truck 20 positionedalongside a reduction pot 10. The pot includes an anode 12, anode sidechannels 14, and several anode pins 16 passing through clearance holesin the channels to provide electrical conection between the anode and anexternal bus system not shown. Conventional portions of truck 20 are thevertically movable carriage 21 and a revolving apron 22 (e.g. Model 40of Cascade Manufacturing Company) supported on the carriage, having arack and pinion drive (not shown) which is actuated by hydrauliccylinders 24 and 25.

Mounted on the apron 22 is a boom housing assembly 26 adapted to supportan extensible boom 28. Hydraulic actuator 30 atop the housing assembly26 has its cylinder pivotably attached to a front bracket 32 on thehousing, and piston rod 34 of the actuator is attached to a rear bracket36 which is affixed to the outer end of the boom. At the opposite end ofthe boom 28 are mounted the puller-driver mechanism 42 and a supportbarrel 46, the construction and operation of which are hereinafterdescribed.

FIG. 4 provides a transverse section through the boom housing assembly26, showing the arrangement by which the boom 28 is mounted forreciprocating movement within the housing. Upper and lower rollers 50having integral flanges 52 afford support and guidance for the boom, andsuitable bearings 54 are arranged at opposite ends of the rollers.Similar sets of upper and lower rollers are spaced lengthwise of theboom, as shown in FIG. 3A.

With reference to FIG. 2, the boom housing assembly 26 is attached tothe rotatable apron 22 by means of a mounting plate 38 which is adaptedto be bolted onto the apron, and a pair of spacer members 40 whichextend between the housing and mounting plate and are welded to each.The inner end of boom 28 (to the left in FIG. 2) is connected to thepuller-driver mechanism 42 through a fork bracket 44 which is bolted inplace as shown (see also FIG. 6). The bracket itself is rigidly joinedto boom 28 by welding. A support barrel 46, adapted to receive aretractable pin clamping head as yet to be described, is attached to thecylinder of pullerdriver mechanism 42 by a coupling 47.

FIG. 6 details the connection of fork bracket 44 to cylinder 56, showingspaced ribs 45 welded inside each leg of bracket 44 to define a slotreceiving the corresponding member 48 welded to cylinder 56. The members48 are tapped to receive bolts 49.

Referring next to FIG. 3B (an enlarged view partially in section alongthe inner end of boom 28), the details of puller-driver mechanism 42 andthe adjoining support barrel 46 are shown. The puller-driver mechanismhas a cylinder 56, back and front heads 57 and 58 providing fluidconnections to the cylinder at opposite ends thereof, and a piston 60.The movement of piston 60 is transmitted through piston rod '62 to a pinclamping head 64 which is slidably received within the support barrel46. FIGURE 5 shows the welded construction of barrel 46 which provides apassageway for reciprocating movement of the pin clamping head 64.

In order to make the necessary transition from the generally rectangularcross-section of cylinder 56 (to which the support barrel is connected),the circular segments 65 are extended outwardly from the rest of the boxsection 66 and into the circular coupling 47. The coupling includes aunion nut 67 which screws onto a threaded extension 68 of cylinder fronthead 58. A ring groove (not shown) is provided adjacent the outer endsof the segments 65 to receive a split ring (not shown) for cooperationwith union nut 67 in the Well known manner of such couplings. Theopposite end of the support barrel has a flange 69 adapted to be seatedagainst the anode side channel 14 when the boom is disposed as shown inFIG. 1.

The pin clamping head 64 (detailed in FIG. 7) has a body made ofnon-magnetic beryllium-copper alloy, in which a threaded socket isprovided for attachment of the piston rod 62. The clamping head isadapted to receive the butt portion 18 of an anode pin 16, as shown, anda pair of pin clamping dogs 76 slidably received within passageways 74are arranged to grasp flat faces 72 of the anode pin in self-lockingmanner. Cover plates 7 8 are removable to afford access for installingthe clamping dogs 76.

Piston-cylinder actuators 80 are provided for engaging and disengagingthe pin clamping dogs. Each actuator has a piston 82 slidably receivedwithin the cylinder bore 84 and carrying a piston ring 83. The plunger86 aflixed to piston 82 passes through a bearing 88 to engage theadjacent pin clamping dog 76. A plug 90 seals the outer end of eachcylinder 84. Fluid is introduced at either side of the piston throughlateral ports such as 92. These ports in turn communicate with aninternal passageway system (not shown) which extends outwardly of thebody 70 for connection to suitable hose fittings at 92 (see FIG. 5).

CONTROL SYSTEM The hydraulic control system is shown schematically inFIG. 8. Conventional portions of the regular truck system include thelift cylinder 94 for raising the truck carriage 21, the tilt cylinder 96for rotating the carriage about a horizontal axis transversely of thetruck, and the lift and tilt valve 98 for controlling cylinders 94 and96. In place of the usual hydraulic source, a pump 106 (Vickers2621Vl4E8-3DDl0) is used to supply both highpressure and low-pressurefluid for purposes which are hereinafter discussed.

The high-pressure outlet 102 of the pump is connected through line 104to inlet port 106 of valve 98. To operate the tilt control cylinder 96,a manual valve operator (not shown} is actuated to pass fluid throughvalve 98 from port 106 to either of ports 108 or 110, depending on whichdirection of movement is desired for tilt cylinder 96. Ports 188 and 110are connected to cylinder 96 through lines 112 and 114, respectively,and as pressure is applied through one line the other is exhausted tosump in accordance with conventional construction and operation of valve98.

The operation of lift cylinder 94 is similar, except that liftingpressure is provided by actuating a second manual valve operator to passfluid through valve 98 from port 106 to outlet port 116, and thence tothe cylinder 94 through lines 118 and 120. The opposite direction ofoperation, lowering the lift mechanism, is accomplished in conventionalmanner by using the weight of the load to force fluid out through lines118 and 120 with port 116 exhausted to sump.

At this point it is convenient to note that the actuators 80 (used forengaging and disengaging the pin clamping dogs) are connected to asource of fluid pressure by means of line 122 tapping into line 120.This arrangement has been found suitable due to the very low volume offluid required for operation of these actuators. In effect, therefore,the load on lift cylinder 94 maintains a pressure in lines 120 and 122which is adequate for this purpose, and the change of fluid volume incylinder 94 occasioned by the requirements of actuators 80 has beenfound to be inconsequential for proper positioning of the liftmechanism. Fluid from line 122 is directed through control valve 124 bypositioning the valve to connect line 122 either to line 125, leading toone set of operators 80 for engaging the pin clamping dogs, or to line126 to actuate the other set of operators 80. When pressure is appliedto line 125, line 126 is connected to sump, and vice versa.

Next to be considered are the control valves 130, 132 and 134 whichrespectively affect operation of the previously described puller-drivermechanism 42, cylinders 24 and 25 for rotating the apron 22, and theboom actuator 30. Fluid pressure is brought to these valves from thehigh-pressure outlet 102 of pump 100 by way of line 104 to port 106 ofvalve 98, as previously discussed, and from there is directed throughvalve '98 by positioning the manual tilt and lift operators in theirneutral condition. Port 106 thereby is connected interiorly ofvalve 98to an outlet leading to the T-connector 136, and thence through lines138 and 140 to control valve 130.

To actuate the puller-driver mechanism 42, in order to extract an anodepin from the carbon anode, valve is positioned to connect supply linewith line 142 leading into cylinder 56. When so positioned, valve 130also connects the outlet line 144 into return line 146 leading back tothe sump 148. With valves 132 and 134 in their neutral condition, it canbe seen that communication is complete between line 146 and the sump byway of lines 150 and 152.

The operation of valves 132 and 134 is similar to that of valve 130. Afirst condition of valve 132 connects pressure line 146 into line 153and through an adjustable flow-control valve 154 to one end of actuator24 and the other end of companion actuator 25, while the return line 155exits through line 150 to sump. A second condition of valve 132 does thereverse. For the boom actuator 30, pressure line 150 is connected toeither of lines 156 and 157 while the other is exhausted to sump vialine 152-. Suitable release valves 158 are disposed at various locationsas shown. All of the manual control valves 98, 124, 130, 132 and 134 aremounted on the truck 20 within convenient reach of the operator orprovide remote control of the corresponding mechanisms previouslydiscussed.

Considerable pressure up to about 1850 psi. may be required in cylinder56 to initially break loose an anode pin from the carbon anode. Afterthe pin is freed, less pressure but considerable volume of flow isneeded for sufiicient travel of the piston rod 62 to retract theclamping head and pin inwardly of the support barrel. For this reason,provision is made for supplementing the flow of fluid into supply line140 once the pressure falls below about 800 p.s.i. (or any other desiredset point). This is accomplished by use of a dump valve 160 connected tothe low-pressure outlet 162 of pump 100 through line 164.

Valve 160 is a type which can be biased automatically in relation to thepressure condition in supply line 140 leading to the various actuatormechanisms. This is accomplished by tapping off from valve 98(previously described) through T-connector 136 to the adjoiningconnector 163, and thence through line to the controller of valve 160.The valve itself is so constructed that its inlet line 164 is connectedinteriorly of the valve either to the outlet line 166 leading to thesump 148, or to the outlet line 168. In the latter condition, fluid fromthe lowpressure side of the pump passes outwardly through line 168,check valve and line 172 to a T-connector 174, where the fluid entersthe supply line between sections 138 and 140.

Which of the two possible outlet conditions will exist is controlled asfollows. If the sensed pressure brought into valve 160 through line 165is greater than a pre-set criterion (typically about 800 p.s.i.), line164 from the pump is connected to outlet line 166 and to sump. In thissituation there is no load on the low-pressure side of the pump. On theother hand, if the sensed pressure is below about 800 p.s.i., line 164is connected to outlet line 168, and a supplemental supply oflow-pressure fluid is directed from line 168 through check valve 170,line 172 and line 140, to furnish an additional volume of fluid. In thismanner, high-pressure fluid is available for initial heavy loadconditions, and increased flow rates are available for low-pressurerequirements after the load decreases.

SUMMARY OF OPERATIONS The steps involved in a complete cycle of pullingand resetting an anode pin may be summarized as follows:

After truck 20 is positioned alongside the pot 10, the operator extendsboom 28 toward the pot (using control valve 134 to actuate cylinder 30).In order to align the boom with the pin 16 to be removed, it may also benecessary to rotate the boom and revolving apron 22 (controlled byoperation of valve 132); and should the pin have become skewed, so thatthe parallel flat faces 72 of the pin butt portion 18 are not disposedvertically, the tilt mechanism 96 is actuated by operating valve 98 toalign the pin clamping head 64 with the pin in this regard.

The boom is extended toward pot until fiange 69 of the support barrel 46is seated against the anode side channel 14, with pin 16 extending intothe pin clamping head 64. Then the pin clamping dogs are engaged withbutt portion 18 of the pin, using valve 124 to actuate the pinengagingset of operators 80, and the clamping head 64 is retracted within thesupport barrel 46 to release the pin from the carbon anode 12. Thisretraction is accomplished by the puller-driver mechanism 42, under thecontrol of valve 130, and it is to be noted particularly that pressureapplied to piston 60 (through line 142 leading from valve 130) causes anopposite and substantially equal reaction force on front head 58 ofcylinder 56, which is transmitted through the coupling 47 to supportbarrel 46, and is directed against the anode side channel 14 by means offlange 69 at the adjacent end of the support barrel.

The clamping head and pin having been moved outwardly from the anode,the entire boom assembly is retracted toward the truck (by positioningvalve 134 to operate boom cylinder 30) and apron 22 is rotated(counterclockwise in FIG. 1) to the extent necessary for the protrudingend of the pin to clear the pot superstructure. Then the truck carriage21 and attached boom mechanism are raised vertically, by operating liftvalve 98 to actuate cylinder 94, in preparation for inserting the pin ata higher level (see phantom outline in FIG. 1).

To align the boom in pin-driving condition, the operator rotates truckapron 22 in the opposite direction (clockwise) to orient pin 16 at thedesired angle for passage through a clearance hole in the anode sidechannel, and extends boom 28 toward the pot until the pin is startedinto the anode 12. Then the pin clamping head is advanced by actuatingpuller-driver mechanism 42 to drive the pin into place, and the pinclamping dogs are disengaged from the pin.

While the presently preferred embodiment of the invention and its methodof operation have been illustrated and described, it will be apparentthat the invention may be otherwise variously embodied and practicedwithin the scope of the following claims.

What is claimed is:

1. Apparatus for extracting an anode pin from the carbon anode of areduction cell, comprising:

an extensible boom carrying a pin clamping head adapted to receive anexposed portion of the pin,

said clamping head having a body including outwardly convergentpassageways and opposed pin clamping dogs slidably supported within saidpassageways for grasping the pin securely therebetween during extractionof the pin;

a truck mounting the boom and remote controls for said boom and clampinghead; and

an actuator system subject to said controls, including means forextending the boom into alignment with the pin to be removed, means toactuate the pin clamping dogs into gripping engagement with said pin,and means for retracting the clamping head relathe pin to be removed,means to actuate the pin from said anode.

2. Apparatus for extracting an anode pin from the carbon anode of areduction cell, said anode being contained within a casing whichincludes an anode side channel or the like having a clearance hole forthe pin, comprising:

a support barrel adapted to be disposed adjacent the anode with theouter end of said support barrel hearing against said channel;

a pin clamping head slidably received within the support barrel, havinga body including outwardly convergent passageways and opposed pinclamping dogs slidably received within said passageways, said clampinghead being mounted for movement back and forth along the barrel betweenan outermost position, in which the clamping head is adapted to receivean exposed portion of the pin extending through the anode side channel,and a retracted position inwardly of the barrel;

means for moving said pin clamping dogs along said passageways of theclamping head in its outermost position to grasp the pin securely forwithdrawal thereof; and

means for retracting the clamping head relative to said barrel to pullthe pin at least partially free from said anode, while reacting anopposing force against the anode side channel through said supportbarrel to compensate for the pulling effort.

3. Apparatus according to claim 2 wherein said means for moving the pinclamping dogs comprises piston-cylinder devices for respectivelyactuating each of said dogs into gripping engagement with the pin andfor releasing the dogs from said pin.

References Cited UNITED STATES PATENTS 2,683,019 7/1954 Saunders et al.254-29 2,964,459 12/ 1960 Pearson 204-243 3,101,798 8/1963 Wilson et al.3,290,005 12/1966 Beemsterboer 25418 FOREIGN PATENTS 99,430 2/1962Norway. 1,110,882 7/1961 Germany.

JOHN H. MACK, Primary Examiner D. R. VALENTINE, Assistant Examiner US.Cl. X.R. 204-67; 254-29

